Problem sorting table columns

I noticed that some columns seem to sort unreliably in one or two tables I had created using the table generator. I examined one particular table; the correct ORDER BY clause was included in the queries for each column and yet one column would not sort correctly - or at least the displayed order would not update. It looked strange, because the other columns were reordered, and yet the column used for sorting remained in the same order - so the data in the same row belonged to different records (rather like what can happen in Excel).

I discovered the only difference with the problem column was that the data was in a data attribute:

<td dmx-text="publication_sortdate" class="text-center"></td>  -- sort order would not update
<td class="text-center">{{publication_sortdate}}</td>          -- sort order correct

Another detail is that the sort order initially seems to work but it won’t switch/toggle - eg it will remain in descending order.

Is this a limitation of using attributes or a bug… ?